1. Field of the Invention
This invention relates to a rotary piston machine having at least one annular conduit which is curved along an at least partial arc and in which a piston is movably supported in a movement-imparting fluid that flows in via a fluid connection and flows out via another fluid connection. The piston is coupled via a lever to a rotating body arranged concentric to the arc and coaxial to the rotation axis of the piston, with the lever routed so that it passes through to the rotating body through a sealed gap, which is in the wall of the annular conduit and extends in the movement direction of the piston.
2. Discussion of Related Art
A rotary piston machine of this kind is disclosed in German Patent Reference DE 91 03 452 U1. In this known rotary piston machine in the form of an oil pressure motor, a piston connected to a drive unit is set into rotation in an annular housing through the exertion of oil pressure. Thus, an oil pressure pump supplies oil to the interior of the housing via an oil pressure line to produce an advancing motion of the piston. To avoid oil-damming energy losses that can arise due to a damming-up of oil between a piston wall and a wall of a sliding element, an interposed suction pump removes oil from this region via a suction line, which should assure a continuously uniform revolution of the piston. The piston is attached to a rotatable piston disk, which is routed so that it passes out of the tubular housing radially through a gap and is attached to a central motor shaft. As the cross section in FIG. 2 of this prior publication shows, the two motor halves encompassing the tubular ring chamber extend over the entire cross-sectional area of the motor, with the shaft passing through at a position between the motor halves. In the embodiment shown, the oil pressure inside the cylinder, after flowing into the cylinder chamber, can spread out uniformly in both directions, with the suction line clearly ending in an oil sump. This design does not achieve a sustained operating function. Also, no information is given regarding a seal, which is essential for the function.
German Patent Reference DD 276 122 A1 discloses a hydraulic motor with a transmitting function, in which certain rotation angle adjustments are possible at low motor speeds. In this instance, flat pistons situated in a segment sleeve affixed to a housing are radially arranged in a sliding fashion around a gear on a shaft that is rotatably supported in the housing. The pistons have a wedge-shaped tip oriented toward the gear and a T-shaped embodiment at the end oriented away from the gear. Oil pushing into a cylinder chamber slides the flat pistons with the wedge-shaped tips into the teeth of the gear. The division difference between the flat pistons and the gear causes the gear to rotate, as a result of which there are always several pistons in operation. The continuous sequential impingement on the flat pistons produces a uniform rotating motion. With this embodiment of the hydraulic motor, it is necessary for a plurality of flat pistons to be moved in a coordinated fashion with one another, with their movement occurring in the radial direction. This design, which provides definite rotation angle adjustments, is relatively complex and is only suitable for relatively slow rotational movements.
French Patent Reference FR 2 500 075 A1 discloses another hydraulic motor having a circular cylinder curved in an arc shape and pistons situated therein that are acted on by the hydraulic medium and attached to a central shaft. Inside the cylinder chamber, there are movably supported flaps that are pivoted into recesses in the cylinder wall in order to make way for the piston to travel through. In this region, there is no effective seal of the piston along the cylinder wall so that there is no guarantee of reliable function. In addition, the pistons can only travel through the cylinder chamber in the inward-pivoting direction of the flaps. Also, the pistons and flaps are subjected to a large amount of wear, so that it is not possible to guarantee long-term function and high torque. The cylinder chamber is encompassed by housing halves attached to each other and that have projections that protrude radially toward the center of the housing and abut a central shaft. Between the projections, a gap is provided through which lever arms are routed, which are attached to the piston at one end and to the central shaft at the other end, with sealing components situated between the projections and the lever arms forming a circular disk. The circular disk-shaped lever arms have recesses for a reduction of pressure.
United Kingdom Reference GB 1 283 907 discloses another rotary piston machine embodied in the form of a metering pump, wherein curved pistons with curved piston rods attached to them are supported in two concentrically opposing semicircular cylinders. The pistons are set into reciprocating motion by a central shaft by a lever, which engages the piston rod, in order to pump a precisely metered quantity of a liquid in a pulsed fashion. In accordance with the curvature of the arc through their cross-sectional area, the ends of the piston rods are each routed so that they pass out of the respective semicircular cylinder and are coupled to the lever outside of the cylinder. As a result of this design, the movement of the piston and shaft is limited to a relatively small angular range, with the design having a primarily synchronizing function. Also, it is difficult to achieve an exact guidance and force transmission between the shaft and piston, particularly at relatively high torques, and the design is unsuitable for transmitting powerful forces and moments.
Piston/cylinder units deflected in a straight line are also widely used for drive purposes, for example to move a lever arm in an excavator. In this instance, the lever arm changes during the pivoting motion, causing a change in the effective moment and the forces involved, particularly also in the bearing positions.
German Patent Reference DE 39 00 375 discloses an internal combustion engine with a piston that smoothly revolves in an annular chamber. The four power cycles of the internal combustion engine in series are integrated into this cylinder chamber. In this instance, it is difficult to achieve a precisely controllable movement sequence over the movement segments. In addition, the design requires complex measures for combustion control, fuel mixture production, and exhaust routing. It is difficult to suitably construct a machine of this kind, particularly with regard to slow movements and high torques. Thus, the current application does not involve an internal combustion engine of this kind.